Much improved yes good probably not but there is potenital for sure and heres why,

The PG's: Both Brooks and Thomas are speed demons who could take turns full court pressuring and going all out on D, they both can be posted up but there is few PG's who are good post up players, they can provide insane energy and pressure and cause havoc for guards bringing the ball up or big men who put the ball on the floor

The SG's: Tyrke, Thorton, Garcia: non of these guys are really anything above average defenders, Tyreke if he applied himself could certainly be a good one conisidering his strength, Thorton has good explosion but i have never really rated his D and while Garcia is smart he just don't have the athletic ability to go with the gun's playing @SG

The SF's: James Johnson and rookie T-Robinson: both athetlic beasts, both tough and can defend from SG-PF (depending on who), Johnson is known as a good defender and Coach Smart has said TROB could be a gun, so i think at SF they are very strong defensivly

The Big's: Cousins lead the league in charges and had good steal and ok block numbers and cause a load of turnovers from other teams, the lost weight in the summer should help if he avoids silly fouls, Chuck Hayes is a defensive monster 6'5 put it don't matter hes just a gun on D. Jason Thompson long range atheltic but needs to get meaner and tougher on D.

I think they can make big improvements on the defensive end but it might take more than one year for them to be a good team although if they work hard the potential is there